The contingent valuation method in health care

The contingent valuation method (CVM) is a survey-based, hypothetical and d irect method to determine monetary valuations of effects of health technolo gies. This comprehensive review of CVM in the health care literature points at methodological as well as conceptual issues of CVM and on willingness t o pay as a measure of benefits compared with other measures used in medical technology assessment. Studies published before 1998 were found by searchi ng computerised databases and former review literature. Studies were includ ed, when performing CVM using original data and meeting qualitative criteri a. Theoretical validity of CVM was sufficiently shown and there were severa l indications of convergent validity. No results on criterion validity and only a few on reliability were found. There was widespread use of, differen t elicitation formats, which make comparisons of studies problematic. Direc t questions were seen problematic. First bids used in bidding games influen ced the monetary valuation significantly (starting point bias). There were indications that the range of bids of payment cards also affected the valua tion (range bias). However, no strategic bias was found. The influence of d ifferent states of valuation (ex-ante, ex-post) and of payment methods, as well as the possible aggregation of the results of decomposed scenarios rat her than more complex holistic scenarios, were rarely investigated. Further methodological analysis and testing seems to be necessary before CVM may b e used in health care decision making. Important research topics are the co nnection of assessment of different elicitation methods and criterion valid ity as well as tests on reliability according to methodological issues. Con cerning conceptual issues, the analysis of the influence of different state s of evaluation and of the status of the respondents as diseased or non-dis eased, as well as the aggregation of results of decomposed scenarios, prove d to be topics of further research. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.